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Question
tan θ cosec2 θ – tan θ is equal to
Options
sec θ
cot2 θ
sin θ
cot θ
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Solution
cot θ
Explanation;
Hint:
tan θ cosec2 θ – tan θ = tan θ (cosec2 θ – 1)
= `tan theta xx cot^2 theta`
= `1/cot theta xx cot^2 theta`
= cot θ
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tan (90 – θ) = ?
Show that, cotθ + tanθ = cosecθ × secθ
Solution :
L.H.S. = cotθ + tanθ
= `cosθ/sinθ + sinθ/cosθ`
= `(square + square)/(sinθ xx cosθ)`
= `1/(sinθ xx cosθ)` ............... `square`
= `1/sinθ xx 1/square`
= cosecθ × secθ
L.H.S. = R.H.S
∴ cotθ + tanθ = cosecθ × secθ
